A far greater health risk, IMO, is the fact that most US and Canadian cattle are fed on grain instead of grass; this leads to fattier beef which increases the risk of heart disease, stroke, and numerous other health problems. If there's any reason to avoid eating beef products, that would be it.

Plus, the beef industry's greedy habit of dosing the cattle with anti-biotics is almost certainly contributing to the rise of anti-biotic resistant microbial beasties, which is not a good thing. <img src="images/graemlins/frown.gif" alt="" />